Originally posted by
Minchandre
By the way, does anyone know if the Greek Orthodox Church was always in Greek, or was first in Latin during the unified Church and then became Greek later?
I'm not sure if initially it was even decided that Latin or Greek would be the official langauge of the Church. I think that using of Latin or Greek by the Church depended of the popularity of a language in local community. In Western Roman Empire Latin was much more popular and acted as a common language for all people - Celts, Germans, Iberians etc. It was because when Romans conquered generally barbaric lands of what later became WRE, they generally had to create their own administration on almost every level, so naturally they used Latin as an official language. Also, they spread their own culture, to replace barbaric ones, so Latin was also a language of civilization and commerce.
OTOH, the territories which later would form the Eastern Roman Empire were generally already civilized enough (by Roman standards), with more or less functional administration and well developed culture. And the language of that culture was Greek. It happened long before Roman conquest, when Alexander the Great's generals divided his empire between themselves and created their own kingdoms, spreading Greek civilization and language. When Romans conquered those kingdoms, they imposed their own governors, but on the medium and low level they generally left local administration alone. They didn't mind local aristocracy, philosophers, artists and merchants speaking Greek, because pretty much every educated Roman spoke Greek. Therefore Greek remained as a common language of most of the local population of ERE.
After the fall of the WRE Latin still remained there as a language of civilization and the Church was the main custodian of that heirloom. Which was why Latin became official language of the Catholic Church, since the Church had to work in many countries and needed a common language. Latin was an obvious choice. And while the ERE survived much longer, the Church there also needed a common lanuage, only there a natural choice was Greek.
It is also good to rememeber, that the Greek is not an official langauge of the Orthodox Church, although AFAIK Orthodox priests are still taught Greek. However, the Orthodox Churches in Russia, Belarus and Ukraine used (and still uses) the Church Slavonic as a liturgical language; the same goes for Armenian, Georgian and other Orthodox churches, which use ancient forms of their own languages. Greek may still serve as a common language (after all the New Testament was originally written in Greek) but it is not the official language of the Orthodox Church, because there is no single Orthodox Church - more like a federation of Orthodox Churches with patriarch of Constantinople as its spiritual leader, but in no way as powerful as the Pope is in the Catholic Church.
I do not know when it was decided that the Latin would be the only official and liturgical language of the Catholic Church. AFAIK the last time the Catholic Church seriously considered allowing some other language as a liturgical one (before the 2nd Vatican Council, of course) was the case of the Slavic rite prepared by Saints Cyril and Methodius in IXth century. Mostly it was abandoned, with Slavic language forbidden as a liturgical langauge, with some exceptions in Croatia and Poland, I think; and there are also Greek Catholic Churches.